We present an overview of ad hoc routing protocols that make forwarding decisions bosed on the geographical position of a packet's destination. Other than the destination's position, each node need know only its own position and the position of its one-hop neighbors in order to forward packets. Since it is not necessary to maintain explicit routes, position-based routing does scale well even i f the network is highly dynamic. This is a major advantage in a mobile ad hoc network where the topology may change frequently; the main prerequisite for position-based routing is that a sender can obtain the current position of the destination. Therefore, recently proposed location services are discussed in addition to position-based packet forwarding strategies. We provided qualitative comparison of the approaches in both areas and investigate opportunities for future research.